There are many applications in academic, industrial, and medical fields that benefit from devices and methods that are capable of accurately and controllably delivering fluids, such as liquids and gases that have a beneficial effect when administered in known and controlled quantities. Such devices and methods can be particularly useful in the medical field where treatments for many patients include the administration of a known amount of a substance at predetermined intervals.
Insulin-injecting pumps have been developed for the administration of insulin for those suffering from both type I and type II diabetes. Recently, continuous subcutaneous insulin injection and/or infusion therapy with portable infusion devices has been adapted for the treatment of diabetes. Such therapy may include the regular and/or continuous injection or infusion of insulin into the skin of a person suffering from diabetes, and offers an alternative to multiple daily injections of insulin by an insulin syringe or an insulin pen. Such pumps can be ambulatory/portable infusion pumps that are worn by the user and that may use replaceable cartridges. Examples of such pumps and various features that can be associated with such pumps include those disclosed in U.S. patent application Ser. No. 13/557,163, U.S. patent application Ser. No. 12/714,299, U.S. patent application Ser. No. 12/538,018, U.S. Provisional Patent Application No. 61/655,883, U.S. Provisional Patent Application No. 61/656,967 and U.S. Pat. No. 8,287,495, each of which is incorporated herein by reference.
Current infusion pumps typically allow for delivery of two infusion types—a basal rate and a bolus delivery. A basal rate typically delivers insulin at a constant rate over an extended period of time and is provided to maintain target glucose levels throughout the day when a user is not eating. Boluses are delivered to counteract carbohydrates consumed at meal times to maintain target glucose levels. For a meal bolus, for example, the user may enter the amount of carbohydrates the user is about to ingest and the user's carbohydrate ratio (the volume of insulin programmed to be delivered for every particular number of carbohydrates predicted to be consumed by the user). Based on this information, the infusion pump will generate an estimate of a bolus amount of insulin to be delivered. If accepted by the user. e.g., by entering a command such as by depressing a button, touching an object on a touchscreen, etc., the then-current basal delivery mode is suspended and the bolus delivery is initiated.
Careful management of insulin delivery in view of carbohydrate consumption, physical activity, and other factors is critical in maintaining the health of type I diabetics. While delivery of insulin is equally important for the overall health of type II diabetics, the specific timing of the delivery and the precise matching of the amount of insulin to carbohydrates consumed is not as critical. In addition, type II diabetics are generally diagnosed only after years of not having to deal with monitoring carbohydrate intake, taking insulin injections. etc. as opposed to type I diabetics who are usually diagnosed at a much younger age. As a result of these and other factors, type II diabetics often do not have the motivation and/or the willingness to diligently monitor their carbohydrate intake, insulin levels, etc. as is required to properly use most insulin pumps.
Therefore, there is a need for an insulin pump and method that is simplified for the treatment of type II diabetics to provide a needed amount of insulin without requiring precise tracking and matching of carbohydrate intake with insulin delivered.